This invention relates to an upper blade holder for a slitter comprising upper and lower revolving blades in shearing relationship.
A slitter comprising upper and lower revolving blades in shearing relationship is employed, for example, for slitting various material webs, such as paper and board webs, foils, magnetic tapes, etc. The upper blade and the lower blade are placed so as to overlap each other partially. As a rule, in a slitter, it is possible to adjust the degree of overlapping of the blades and the force that presses the blades together as well as the toe-in angle between the blades.
In a known slitter, in which a pneumatic cylinder is used for lowering the upper blade into engagement into the lower blade, various problems and drawbacks have occurred in the upper blade holder. For example, the operation of the pneumatic cylinder has not always been satisfactory during its operating stroke. Also, when the web to be slit is fed to the slitter in a horizontal plane, the operation of the mechanism for adjusting the overlapping of the upper and lower blades has been to some extent dependent on the position of the blades. The mounting and the protection of the blade and the blade support in the known slitter also leave room for improvement.
U.S. Pat. No. 3,956,957 discloses a device for slitting webs, wherein the upper and lower blades can be engaged and disengaged both in the radial direction and in the axial direction by use of a single handle. The device in accordance with this U.S. patent does not suggest a solution for elimination of the problems mentioned above.